Wedge shaped shoulder pads are used on shoulder straps to cushion straps that do not conform to the slope of a person's shoulder. Most individuals have shoulders that slope downwardly and outward from their neck. Shoulder straps are generally straight straps that tend to extend horizontally at the top of the loop that passes over a person's shoulder. This results in the inside edge of a shoulder strap exerting more pressure on a person's shoulder than the center portion or the outside edge of a shoulder strap. This concentration of pressure makes it uncomfortable to carry a bag or a piece of equipment with a shoulder strap. If the bag or equipment is heavy, the concentration of pressure may become painful in a short period of time.
Straight shoulder straps also tend to slide off a person's shoulder. With the outside edge of a shoulder strap being lightly loaded, the strap tends to slide down a sloping shoulder. To keep the strap from falling off a person has to move the strap back toward their neck periodically.
Wedge shaped shoulder pads have been proposed to evenly distribute the pressure and reduce sliding. These pads distribute the load more evenly when the shoulder strap is centered on the pad. The pad can however slide off a person's shoulder. The shoulder strap can also slide off the shoulder pad.
Shoulder pads have been attached to the shoulder straps by a variety of retainers. These retainers can break. Some of the retainers have also allowed shoulder pads to slide out from under the shoulder strap.